Water level indicating device for a dishwasher

ABSTRACT

A water level indicating device for a dishwasher provided with a cabinet, inside which is placed a washer tub ( 1 ), and presenting a control unit, which determines the operational conditions of providing or interrupting the water supply to the inside of the washer tub ( 1 ), said device comprising: a first chamber ( 10 ) in fluid communication with the washer tub ( 1 ); a second chamber ( 20 ) having a lower portion ( 21 ) maintained in fluid communication with a lower portion ( 11 ) of the first chamber ( 10 ); and a level sensor ( 2 ), which is operatively associated with both the second chamber ( 20 ) and the control unit, in order to inform the latter about a water level detected inside said second chamber ( 20 ) and corresponding to a desired filling level of the washer tub ( 1 ).

FIELD OF THE INVENTION

The present invention refers to a water level indicating device for adishwasher, particularly to be applied in small and medium sizedishwashers.

PRIOR ART

Dishwashers have a cabinet, which is usually parallelepipedic and closedby a vertical door, and inside which is mounted a washer tub designed toreceive a determined quantity and type of dishes to be cleaned. For thewashing operation, after closing the door and starting the washingoperation, the washer tub is filled with water, up to a certainpredetermined filling level, which, when achieved, is informed to acontrol unit that commands the interruption of water supply to thedishwasher.

The small and medium size dishwashers present, mounted inside thecabinet and adjacent and external to the washer tub, a level sensor influid communication with said washer tub through a duct arranged in avessel communicating system. In the known constructions, the levelsensor is mounted to a float provided inside a level duct in fluidcommunication with the washer tub and which is disposed substantiallyvertical, parallel and adjacent to a rear wall of said washer tub, saidlevel duct having a lower end opened to a lower portion of the washertub, in order to receive the filling water for the latter, and a ventedupper end, through which is mounted the float with the level sensor.

In these constructions, the level sensor informs the control unit when apredetermined water level has been achieved inside the washer tub,allowing said control unit to start the washing operation. In suchconstructions, the level sensor may also, for example, inform thecontrol unit about a minimum water level, indicating that either thewasher tub has been drained, or, in a filling condition, that theminimum water level has not been achieved to allow the washing operationto start.

In these dishwashers, the grease of the dishes contained in the washingwater inside the washer tub also reaches the level duct where the levelsensor is located, impregnating in these elements and graduallyinterfering with the adequate operation of the level sensor, or evencausing operational defects in the float that carries said level sensor.

SUMMARY OF THE INVENTION

Thus, it is an object of the present invention to provide a water levelindicating device for a dishwasher, which minimizes the contact of thelevel sensor with the impurities existing in the washing liquid,particularly grease, thus preventing the inadequate operation of thefloat that carries said level sensor and consequently of said levelsensor and said dishwasher.

A more specific object of the present invention is to provide a waterlevel indicating device, such as that mentioned above which, in case offailure of its level sensor, prevents the dishwasher from working whenthe latter does not present effective operational conditions, forexample, due to insufficient water therein.

These and other objectives are achieved by a water level indicatingdevice for a dishwasher having a cabinet, inside which is provided awasher tub, and presenting a control unit, which determines theoperational conditions of providing or interrupting the water supply tothe inside of the washer tub, said device comprising: a first chamber,in fluid communication with the washer tub; a second chamber, having alower portion maintained in fluid communication with a lower portion ofthe first chamber; and a level sensor, which is operatively associatedwith both the second chamber and the control unit, in order to informsaid control unit about a water level detected inside said secondchamber and corresponding to a desired filling level of the washer tub.

BRIEF DESCRIPTION OF THE DRAWINGS

The following invention will be described below, with reference to theattached drawings, in which:

FIG. 1 illustrates a longitudinal sectional view of an embodiment of thewater level indicating device for a dishwasher of the present invention,to be mounted inside the cabinet of the dishwasher, externally to thewasher tub thereof and carrying two floats therewithin;

FIG. 2 is an upper view of the embodiment for the water level indicatingdevice illustrated in FIG. 1, without the cover upper portion of saiddevice;

FIG. 3 is a perspective view of the device of FIG. 2;

FIG. 4 is a perspective view of a chamber divider of the device of thepresent invention;

FIG. 5 is a perspective view of the cover of the present device; and

FIGS. 6 and 7 illustrate a perspective view of each float with therespective level sensor of the device of the present invention.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

The present invention will be described in relation to a small or mediumsize dishwasher of the type comprising, inside a non-illustratedcabinet, a washer tub 1, which receives the dishes to be cleaned, andexternal and adjacent to said washer tub, and inside the cabinet, thewater level device of the present invention.

The dishwasher further comprises a control unit, not illustrated, whichdetermines the operational conditions for providing and interrupting thewater supply to the inside of the washer tub 1, based on the informationreceived from a level sensor 2, provided inside the present device, asdescribed below and which indicates when the filling water of thedishwasher achieves a determined level in said water level indicatingdevice corresponding to a certain water level within the washer tub 1.Upon receiving this information from the level sensor 2, the controlunit commands the interruption of water supply to the washer tub 1 andthe start of the washing operation. In a possible option, the levelsensor 2 further informs the control unit when the water inside thedevice of the present invention achieves a minimum water level,indicating the washer tub 1 has been drained and that it may thus berefilled.

According to the present invention, the water level indicating device ofthe present invention comprises a first chamber 10 in fluidcommunication with the washer tub 1, and a second chamber 20, having alower portion 21 maintained in fluid communication with a lower portion11 of the first chamber 10 and to which are operatively associated thelevel sensor 2 and the control unit, so that the level sensor 2 detectsand informs said control unit about at least one water level, which ispreviously defined and achieved by the water being supplied to theinside of said second chamber 20 corresponding to a respective anddesired filling level of the washer tub 1.

The level sensor 2 is displaceable inside the second chamber 20 betweena first position and a second position, which are axially spaced formeach other and respectively correspond to the conditions of presence ofwater inside the second chamber 20, below and on a certain predeterminedfilling level of said second chamber 20.

In the illustrated constructive option, the water level indicatingdevice comprises a hollow body 40, inside which are defined at leasttwo, for example three chambers 10, 20, 30, in fluid communication witheach other and with the washer tub 1, as described below, said hollowbody 40 presenting a first end 41 a, opened to the washer tub 1 andproviding fluid communication with the latter and with the first chamber10, and a second end 41 b, vented to the atmosphere and whereto ismounted the level sensor 2. In the illustrated constructive option, thehollow body 40 is coupled to the washer tub 1 through its first end 41 aand receives, through its second end 41 b, a first float 50, which isdisplaceable inside the second chamber 20 and carries the level sensor2, and, through a third end 41 c, a second float 60 actuating inside thethird chamber 30, and a safety sensor 70 associated with said secondfloat 60. The safety sensor 70 is provided inside the third chamber 30in a vertical higher position than that of the level sensor 2 in itsposition corresponding to a maximum filling condition of the washer tub1, so as to inform the control unit that a maximum filling limit of thewasher tub 1 has been achieved.

Each float is made of plastic material, for example. The first float 50carries a magnetic element, such as a magnet, which allows its movementin the respective chamber.

In the illustrated construction, the hollow body 40 is closed by a cover43 carrying both the level sensor 2 and the safety sensor 70 and whichis affixed to the hollow body 40, closing the latter by fitting each ofa plurality of ears 44 provided in a lower skirt portion of said cover43, into a corresponding tooth 45 provided in an upper portion of thehollow body 40. In this construction, the cover 43 presents, from anexternal face thereof, first and second vented tubular projections 46,47, said first tubular projection 46 lodging the first float 50 and thelevel sensor 2 and said second tubular projection 47 lodging the safetysensor 70 and the second float 60.

The first float 50 presents a buoy portion 51 and a rod portion 52projecting from said buoy portion 51 and provided with grooves 53, forexample orthogonal to each other, a free end of said rod portion 52presenting a magnet 54 and said second float 60 comprising a respectivebuoy 61 and an arm 62 projecting from an upper end edge of therespective buoy 61 and presenting, for example, a curved shape,particularly spacing away from said buoy 61, said arm 62 beingarticulated by an end 63 to a portion of the second tubular projection47.

The first tubular projection 46 presents, internally along its length,at least one pair of longitudinal guides 48, which are for example,continuous and opposite to each other, and which will receive respectivegrooves 53 of the rod portion of the first float 50, in order to avoidthat, when water is supplied to and drained from said chamber 20, saidfirst float 50 presents other movements than the vertical displacementto and from said first tubular projection 46.

The safety sensor 70 is mounted to the vented portion of the secondtubular projection 47 of the cover 43 and is actuated by a switch, whoseoperation is defined as a function of the movement of the second float60 inside the third chamber 30.

According to the illustrated constructive option, the hollow body 40 ofthe water level indicating device 10 of the present invention carries adivider 80, for example in a single piece mounted inside said hollowbody 40, in order to define therein the first, the second and the thirdchambers 10, 20 and 30, said first chamber 10 being positioned betweenthe other chambers and having its lower portion opened to the first end41 a of the hollow body 40. As a function of the construction of thedivider 80, the latter defines, for each chamber of the hollow body 40,a respective lower opening on the same level inside the hollow body 40.

The hollow body 40 presents, internally, in a lower portion of eachlateral wall, internal projections 40 a, which define guides for theintroduction and fixation of the divider 80. In the illustratedconstruction, each lateral wall includes three internal projections 40a, one of each being vertically longer and determining the support forthe portion of the divider 80 that defines the third chamber 30.

The hollow body 40 presents a bottom wall with a “V” profile, in orderto allow water to be drained when said hollow body 40 is emptied. In thevertex region of said “V” profile is provided a lateral nozzle 49located in the hollow body 40 and which is opened to the first end 41 a,for example being tooted and receiving a sealing ring, not illustrated,for mounting the present device to the washer tub 1.

The divider 80 presents a flat central structure, from which uppercontour project, to each side of said structure, flanges 81 providedwith holes 82, each hole for receiving a fitting end of an internalprojection 40 a provided in an internal lateral wall of the hollow body40.

In a way of carrying out the present invention, the level sensor 2 is amagnetic sensor and the safety sensor 70 is an electrical switch, saidsensors being provided in order to, respectively, detect a minimum waterlevel and a maximum water level in the dishwasher, and each sensor beingmounted on a respective printed circuit board provided in the cover 43of the hollow body 40 of the present device.

The safety sensor 70 operates independently of the level sensor 2,preventing the water from flowing out of the dishwasher in case thelevel sensor 2 fails to detect the water level. After receiving theinformation from said safety sensor 70 that the water level has reacheda predetermined maximum value and, therefore, indicating the operationof the level sensor 2 has failed, the control unit commands thedeenergization of a water inlet valve and the energization of a drainagepump, for promoting the partial or total emptying of the washer tub 1.In the illustrated construction, the water supply and water discharge inthe hollow body 40 is made through the same opening, represented by thefirst end 41 a of said hollow body 40.

The device of the present invention minimizes reading errors of thewater levels and reduces risks of water overflowing from said washer tub1.

1. A water level indicating device for a dishwasher provided with acabinet, inside which is placed a washer tub (1), and presenting acontrol unit, which determines the operational conditions of providingor interrupting the water supply to the inside of the washer tub (1),characterized in that it comprises: a first chamber (10) in fluidcommunication with the washer tub (1); a second chamber (20) having alower portion (21) maintained in fluid communication with a lowerportion (11) of the first chamber (10); and a level sensor (2), which isoperatively associated with both the second chamber (20) and the controlunit, in order to inform said control unit about a water level detectedinside said second chamber (20) and corresponding to a desired fillinglevel of the washer tub (1).
 2. Device, according to claim 1,characterized in that it comprises a hollow body (40) defining,internally, first and second chambers (10, 20), said hollow body (40)presenting a first end (41 a) opened to the washer tub (1) and providingfluid communication between the latter and the first chamber (10). 3.Device, according to claim 2, characterized in that the hollow body (40)presents a vented second end (41 b), whereto is mounted the level sensor(2), which is defined in the second chamber (20) spaced from the lowerportion of the latter that is in fluid communication with the firstchamber (10).
 4. Device, according to claim 1, characterized in that thelevel sensor (2) is displaceable inside the second chamber (20) betweena first position and a second position, which are axially spaced fromeach other and respectively correspond to the conditions of presence ofwater in the second chamber (20), below and on a certain predeterminedfilling level of said second chamber (20).
 5. Device, according to claim4, characterized in that the level sensor (2) is mounted to a firstfloat (50), provided inside the second chamber (20).
 6. Device,according to claim 1, characterized in that the hollow body (40) iscoupled to the washer tub (1) through its first end (41 a).
 7. Device,according to claim 6, characterized in that the first and the secondchambers (10, 20) are separated from each other by a divider (80)carried by the hollow body (40).
 8. Device, according to claim 7,characterized in that the divider (80) is a piece mounted inside thehollow body (40) defining inside the latter the first and the secondchambers (10, 20).
 9. Device, according to claim 6, characterized inthat it includes a safety sensor (70) provided in a third chamber (30)having a respective lower portion in fluid communication with the firstchamber (10) through a lower opening in the latter, said safety sensor(70) being operatively associated with both the control unit and saidthird chamber (30), in order to detect the water level existing therein,informing this detected level to the control unit.
 10. Device, accordingto claim 9, characterized in that the safety sensor (70) is mounted to asecond float (60) provided in said third chamber (30), said safetysensor (70) being actuated when the washing liquid inside said thirdchamber (30) reaches a level in the latter that is higher than thatlevel actuating the level sensor (20).
 11. Device, according to claim 9,characterized in that the third chamber (30) is defined in the hollowbody (40) by the divider (80) and that said third chamber (30) ispositioned in said hollow body (40) in order to have a common wall withthe first chamber (10).
 12. Device, according to claim 9, characterizedin that the hollow body (40) is superiorly closed by a cover (43),through which is mounted at least one of the level sensor (2) and safetysensor (70).
 13. Device, according to claim 12, characterized in thatthe cover (43) carries a first and a second tubular projection (46, 47)for respectively mounting the first and the second floats (50, 60).